Dynamic Leaching Studies on Pulpwood Bark Residues

Recent years have witnessed a growing concern by the pulp industry over the effect of bark disposal operations on receiving water quality. In these circumstances the National Council of the Paper Industry for Air and Stream Improvement, Inc., undertook a laboratory study to define the quantities of BOD₅, COD, and color leached from fresh and field-aged pulpwood bark residues under several experimental conditions. Barks from northeastern species were used in all investigations. The results showed that the quantity of BOD₅, COD, and color leached from bark residues under dynamic leaching conditions depends on the field storage age of the bark, and on the conditions under which leaching occurs. Working curves for estimating BOD₅, COD, and color contributions from northeastern pulpwood bark residues are presented.